After rounding up the five men accused of gangraping a 22-year-old photojournalist, the police are now looking for a ragpicker who they believe passed the scene of crime at Shakti Mill compound in Mahalaxmi while the photojournalist was being raped.

The ragpicker could become the
prime witness in the case and help nail the accused, a senior officer said. "We are gathering details about this ragpicker. If we find him, it will help prove the crime."

Apart from him, the police have no independent eyewitnesses, though they believe they have sufficient scientific evidence to secure a conviction.

Home minister RR Patil on Monday said the police would file the charge sheet at the earliest. A charge sheet has to be filed within 90 days of the case being registered. While Patil has already met special public prosecutor Ujjwal Nikam, he has directed his department to consult the family members of the survivor for their choice before appointing the prosecutor.

Sources said the crime branch is expected to file the chargesheet in a month's time. "Rather than hurrying to submit the charge sheet, we would rather have a strong and comprehensive charge sheet even if it is delayed by a few days," the officer said.

Mumbai police commissioner Satyapal Singh has reiterated that the case would be tried in a fast-track court.

The police also got the five accused to undergo a potency test at JJ hospital on Monday. "The accused in a rape case try to use the argument that they are impotent and incapable of rape. We want to eliminate that defence ploy at the outset," the officer said.

Officials are confident that the evidence they will have against the accused through DNA tests and 'scene of crime rummaging' technique will help them prove the presence of the accused and the survivor at the scene of crime.

The police also expect that the mobile phones of two of the accused - Mohamed Kasim Hafiz Sheikh, alias Bangali, and Mohamed Salim Ansari - will prove their presence at the scene of crime and the sequence of events. While the police have seized Ansari's phones, they are yet to recover Shaikh's mobile phone, which he lost while gambling. "There is a Google mapping technology that will help us prove their movements," the officer said.

Ansari had taken a photo of the survivor, but later deleted it. "There is a technology by which deleted items can be retrieved. We will send the mobile phone to the forensic laboratory. Its result will be added to the chargesheet," the officer added.

The survivor's vaginal smear samples will be tested with the DNA of the accused to prove rape.